Vault of the Dreamer

The Vault of the Dreamer is the third and final Vault on Pandora, identified by the Gemini Corporation and cloaked from the Vault Key. It was constructed by the Eridians once they realised that the Dreamer was going to resurrect itself following its defeat, and was designed with maximum security to prevent the rogue unit from escaping its prison.

As a result, the Dreamer was chained within the Vault itself, and could not leave. It was only able to escape its chains once in the presence of two Sirens, and one half-Siren, however it remained within the arena until the fight ended.

Matt Rye spent several months searching for this Vault, getting closer using his Vault Instincts, however the Vault was found by Gemini first and a cloaking mechanism was deployed to hide its presence on the planet and make it nearly untrackable. The Infinite energy signature it gave off was the only reason it wasn't hidden from the Anomaly completely.

The Dreamer
When the Vault was constructed by the Eridians for one sole purpose: imprisoning the Dreamer. Following the Dreamer going rogue and attempting to destroy them, they placed the Dreamer within suspended animation, until they discovered Infinite energy signatures coming off from it and discovered the Infinite. They realised that this energy leak was a sign that the unit was going to reanimate and attack them once more. Thus, the Vault of the Dreamer was built to imprison it. The Dreamer was trapped inside and was unable to leave due to the Eridians deliberately not implementing a Vault Key interface to open it.

Other Inhabitants

 * -|After Dreamer fight=
 * Amelia Rye (various)
 * The Enlightener
 * Fiona (teleported)
 * Innumerable Crimson Raiders (mostly deceased)
 * Five
 * Four
 * James Sharp
 * Three
 * Two
 * Rhys (teleported)
 * Numerous Gemini soldiers (deceased)
 * -|During Dreamer fight=
 * Arcturus Vaus
 * Aurora Lux
 * Axton
 * Brick
 * Caine Brooke
 * Daniel Marx
 * Duke Minoosh
 * Gaige
 * Krieg
 * Lilith
 * Matt Rye (various)
 * Maya
 * Mordecai
 * Violet Parker
 * Zer0
 * -|Before Dreamer fight=
 * Eridians
 * the Watcher

Format
The Vault of the Dreamer is the only known Vault that cannot be opened with a conventional Vault Key. The Eridians purposefully designed this as they never intended the Dreamer to be encountered under any circumstances, not even in desperation. However, a living Vault Key was eventually created by Hyperion, which could open the prison.

The Vault also phased between the Infinite and Midgard every two hundred years or so, at the same rate at which the Vault Key charged. This drew from the Dreamer's power, in order to weaken through the strenuous energy required to shift dimensions and thus degrade its connection to the Infinite.

However, it could be forcefully brought into Midgard permanently through use of the latter living Vault Key, Matt Rye. While Matt remained alive, he subconsciously kept the Vault closed within the Infinite while its due time to return to Midgard approached. However, the Vault was energising over time, weakening this ability. Additionally, when Matt cheated death during the Friendship Gulag incident, his sister was able to prey on his now enhanced connection to the Infinite and do the same. Once the Vault fully materialised, it was secured by Gemini (who had found the spot of its phasing prior) and made invisible.

The Vault was only opened once Matt provided a surge of Infinite energy that only he drew from.

Status
Once the Dreamer was defeated, the Vault's connection to the Infinite was cut off. non-volatile Infinite energy leaked out into Midgard following Rhys and Fiona being teleported there and reopening the Vault. This resulted a rise of Eridium resources that were quickly taken by numerous corporations.

Since it exists within the Infinite, it still stored Infinite energy, however the gateway closed off and it was left stuck in a pocket dimension within the Echelon Low, therefore it could not longer be accessed and the Vault door was left behind and useless.

When Matt returned, the Vault was re-energised, its connection restored for a time. The Infinite energy was then absorbed by himself and his sister, although much of the energy had already leaked out. Upon their leaving the Vault, it was yet again sealed off and made inaccessible. The Vault door remains in its spot permanently, although the prison inside returned to the Infinite.

Trivia

 * The Vault of the Dreamer's properties of only appearing every 200 hundred years is based off the musical Brigadoon, which is about a scottish village that only appears every 100 years before vanishing into a mist. Matt passing into the Infinite is somewhat reminiscent of Tommy's ultimate decision of whether to stay in Brigadoon or not.